In this paper the three-dimensional unsteady aerodynamics of a low aspect ratio, high pressure turbine stage are studied. In particular, the results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX, are critically evaluated against experimental data. Measurements were carried out with a novel three-dimensional fast-response pressure probe in the closed-loop test rig of the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano. An analysis is first reported about the strategy to limit the CPU and memory requirements while performing three-dimensional simulations of blade row interaction when the rotor and stator blade numbers are prime to each other. What emerges as the best choice is to simulate the unsteady behavior of the rotor alone by applying the stator outlet flow field as a rotating inlet boundary condition (scaled on the rotor blade pitch). Thanks to the reliability of the numerical model, a detailed analysis of the physical mechanisms acting inside the rotor channel is performed. Two operating conditions at different vane incidence are considered, in a configuration where the effects of the vortex-blade interaction are highlighted. Different vane incidence angles lead to different size, position, and strength of secondary vortices coming out from the stator, thus promoting different interaction processes in the subsequent rotor channel. However some general trends can be recognized in the vortex-blade interaction: the sense of rotation and the spanwise position of the incoming vortices play a crucial role on the dynamics of the rotor vortices, determining both the time-mean and the time-resolved characteristics of the secondary field at the exit of the stage.

References

References
1.
Paniagua
,
G.
,
Yasa
,
T.
,
de la Loma
,
A.
,
Castillon
,
L.
, and
Coton
,
T.
, 2008, “
Unsteady Strong Shocks Interactions in a Transonic Turbine: Experimental and Numerical Analysis
,”
AIAA J. Propul. Power
,
24
, pp.
722
731
.
2.
Sieverding
,
C. H.
, 1985, “
Recent Progress in the Understanding of Basic Aspects of Secondary Flows in Turbine Blade Passages
,”
ASME J. Eng. Gas Turbine Power
,
107
, pp.
248
257
.
3.
Ong
,
J.
, and
Miller
,
R. J.
, 2012, “
Hot Streak and Vane Coolant Migration in a Downstream Rotor
,”
ASME J. Turbomach.
,
134
, p.
051002
.
4.
Doorly
,
D. J.
, 1988, “
Modeling the Unsteady Flow in a Turbine Rotor Passage
,”
ASME J. Turbomach.
,
110
, pp.
27
33
.
5.
Stieger
,
R. D.
, and
Hodson
,
H. P.
, 2005, “
The Unsteady Development of a Turbulent Wake Through a Downstream Low-Pressure Turbine Blade Passage
,”
ASME J. Turbomach.
,
127
, pp.
388
394
.
6.
Chaluvadi
,
V. S. P.
,
Kalfas
,
A. I.
,
Benieghbal
,
M. R.
,
Hodson
,
H. P.
, and
Denton
,
J. D.
, 2001, “
Blade-Row Interaction in a High-Pressure Turbine
,”
AIAA J. Propul. Power
,
17
, pp.
892
901
.
7.
Pullan
,
G.
, and
Denton
,
J. D.
, 2003, “
Numerical Simulation of Vortex-Turbine Blade Interaction
,”
Proceedings of the 5th European Conference on Turbomachinery
.
8.
Gaetani
,
P.
,
Persico
,
G.
,
Dossena
,
V.
, and
Osnaghi
,
C.
, 2007, “
Investigation of the Flow Field in a HP Turbine Stage for Two Stator-Rotor Axial Gaps—Part II: Unsteady Flow Field
,”
ASME J. Turbomach.
,
129
, pp.
580
590
.
9.
Chaluvadi
,
V. S. P.
,
Kalfas
,
A. I.
,
Hodson
,
H. P.
,
Ohyama
,
H.
, and
Watanabe
,
E.
, 2003, “
Blade Row Interaction in High-Pressure Steam Turbine
,”
ASME J. Turbomach.
,
125
, pp.
14
24
.
10.
Persico
,
G.
,
Gaetani
,
P.
, and
Osnaghi
,
C.
, 2009, “
A Parametric Study of the Blade Row Interaction in a High Pressure Turbine Stage
,”
ASME J. Turbomach.
,
131
, p.
031006
.
11.
Denton
,
J. D.
, 1993, “
Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
,
115
, pp.
621
656
.
12.
Pullan
,
G.
, 2006, “
Secondary Flows Caused By Blade Row Interaction in a Turbine Stage
,”
ASME J. Turbomach.
,
128
, pp.
484
491
.
13.
Gaetani
,
P.
,
Persico
,
G.
, and
Osnaghi
,
C.
, 2010, “
Effects of Axial Gap on the Vane-Rotor Interaction in a Low Aspect Ratio Turbine Stage
,”
AIAA J. Propul. Power
,
26
, pp.
325
334
.
14.
Gaetani
,
P.
,
Persico
,
G.
,
Dossena
,
V.
, and
Osnaghi
,
C.
, 2007, “
Investigation of the Flow Field in a HP Turbine Stage for Two Stator-Rotor Axial Gaps—Part I: Three-Dimensional Time-Averaged Flow Field
,”
ASME J. Turbomach.
,
129
, pp.
572
579
.
15.
Dossena
,
V.
,
Gaetani
,
P.
, and
Persico
,
G.
, 2004, “
Development of High Response Pressure Probes for Time-Resolved 2D and 3D Flow Measurements in Turbomachines
,”
17th Symposium on Measuring Techniques in Turbomachines
, Stockholm, Sweden.
16.
Persico
,
G.
,
Gaetani
,
P.
, and
Guardone
,
A.
, 2005, “
Design and Analysis of New Concept Fast-Response Pressure Probes
,”
Meas. Sci. Technol.
,
16
, pp.
1741
1750
.
17.
Wilcox
,
D. C.
, 1988, “
Reassessment of the Scale Determining Equation for Advanced Turbulence Models
,”
AIAA J.
,
26
, pp.
1299
1310
.
18.
Menter
,
F. R.
, 1993, “
Zonal Two Equation k-ω Turbulence Models for Aerodynamic Flows
,” AIAA Paper 93-2906.
19.
Erdos
,
J. I.
,
Alzner
,
E.
, and
McNally
,
W.
, 1977, “
Numerical Solution of Periodic Transonic Flow Through a Fan Stage
,”
AIAA J.
,
15
, pp.
1559
1568
.
20.
Giles
,
M. B.
, 1988, “
Calculation of Unsteady Wake/Rotor Interaction
,”
AIAA J. Propul. Power
,
4
, pp.
356
362
.
21.
Gerolymos
,
G. A.
,
Michon
,
G. J.
, and
Neubauer
,
J.
, 2002, “
Analysis and Application of Chorochronic Periodicity in Turbomachinery Rotor/Stator Interaction Computations
,”
AIAA J. Propul. Power
,
18
, pp.
1139
1152
.
22.
Persico
,
G.
,
Savini
,
M.
, and
Mora
,
A.
, 2008, “
On the Calculation of the Unsteady Flow in a Low Aspect Ratio Turbine Stage
,”
Proceedings of the 63rd Congresso Nazionale ATI
.
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